the end product of photosynthesis in plants are oxygen plus

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What Is the End Product of Photosynthesis?

Describe What a Photosystem Does for Photosynthesis

Humans and most other animals need certain things to survive. Oxygen is one of them, and the carbohydrate glucose is another. Fortunately for them, plants (and certain bacteria and algae) produce both of these as the result of a complex process known as photosynthesis.

The Formula

The formula associated with the process of photosynthesis is

6H 2 O + 6CO 2 = C 6 H 12 O 6 + 6O 2 .

This formula tells you is that six molecules of water plus six molecules of carbon dioxide will produce one molecule of glucose plus six molecules of oxygen. This entire process goes through two distinct stages before it is completed. The first stage is a light-dependent process and the second stage is a light-independent process.

Light Dependent

In the light-dependent process, the electrons of the chloroplasts (special organelles used to carry out photosynthesis) are excited into a higher energy state when they are bombarded with light. These excited electrons cause a series of reactions that produce adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH). ATP and NADPH are then used to make carbon bonds in the light-independent process. Water molecules present in the light-dependent process are split. Their oxygen molecules are released into the atmosphere.

Light Independent

Recall the splitting of the water molecules in the light-dependent process that released oxygen molecules into the atmosphere. Since water is H 2 0, there is still a hydrogen atom remaining. This hydrogen atom is used in the light-independent process when plants take carbon dioxide from the atmosphere. The carbon dioxide and hydrogen become bound together through a process called carbon fixation, which forms a non-specific carbohydrate.

Photophosphorylation

Photophosphorylation is the process by which light energy produces NADPH. Special pigments found in the plant’s cells known as chlorophyll make this process possible. The two main types of chlorophyll are chlorophyll A and chlorophyll B. In simple terms, the electrons of water molecules present in chlorophyll B become excited by the presence of light. Chlorophyll B takes one of these excited electrons splitting the H 2 O molecule into H + and O -2 . O -2 is converted into O 2 and released into the atmosphere. The excited electron is attached to a primary electron receptor, and through a series of complex reactions forms NADPH. NADPH is the energy carrier used in carbon fixation.

The Calvin Cycle

Plants produce glucose in a process known as the Calvin cycle. The carbon dioxide captured in the light-independent process is processed in this cycle. For every six molecules of carbon dioxide captured and put into the cycle, one molecule of glucose is produced. The chemical that captures the carbon dioxide for use in the Calvin cycle is ribulose biphosphate.

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About the Author

Kelley Boles obtained his B.A. in writing from the University of Central Arkansas in 2005. He has been a freelance writer within his community ever since. His most ambitious project today has been the writing of a comprehensive assembly manual for BBQ smokers manufactured by Royal Oak Enterprises LLC.

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ENCYCLOPEDIC ENTRY

Photosynthesis.

Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.

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Learning materials, instructional links.

• Photosynthesis (Google doc)

Most life on Earth depends on photosynthesis .The process is carried out by plants, algae, and some types of bacteria, which capture energy from sunlight to produce oxygen (O 2 ) and chemical energy stored in glucose (a sugar). Herbivores then obtain this energy by eating plants, and carnivores obtain it by eating herbivores.

The process

During photosynthesis, plants take in carbon dioxide (CO 2 ) and water (H 2 O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose. The plant then releases the oxygen back into the air, and stores energy within the glucose molecules.

Chlorophyll

Inside the plant cell are small organelles called chloroplasts , which store the energy of sunlight. Within the thylakoid membranes of the chloroplast is a light-absorbing pigment called chlorophyll , which is responsible for giving the plant its green color. During photosynthesis , chlorophyll absorbs energy from blue- and red-light waves, and reflects green-light waves, making the plant appear green.

Light-dependent Reactions vs. Light-independent Reactions

While there are many steps behind the process of photosynthesis, it can be broken down into two major stages: light-dependent reactions and light-independent reactions. The light-dependent reaction takes place within the thylakoid membrane and requires a steady stream of sunlight, hence the name light- dependent reaction. The chlorophyll absorbs energy from the light waves, which is converted into chemical energy in the form of the molecules ATP and NADPH . The light-independent stage, also known as the Calvin cycle , takes place in the stroma , the space between the thylakoid membranes and the chloroplast membranes, and does not require light, hence the name light- independent reaction. During this stage, energy from the ATP and NADPH molecules is used to assemble carbohydrate molecules, like glucose, from carbon dioxide.

C3 and C4 Photosynthesis

Not all forms of photosynthesis are created equal, however. There are different types of photosynthesis, including C3 photosynthesis and C4 photosynthesis. C3 photosynthesis is used by the majority of plants. It involves producing a three-carbon compound called 3-phosphoglyceric acid during the Calvin Cycle, which goes on to become glucose. C4 photosynthesis, on the other hand, produces a four-carbon intermediate compound, which splits into carbon dioxide and a three-carbon compound during the Calvin Cycle. A benefit of C4 photosynthesis is that by producing higher levels of carbon, it allows plants to thrive in environments without much light or water. The National Geographic Society is making this content available under a Creative Commons CC-BY-NC-SA license . The License excludes the National Geographic Logo (meaning the words National Geographic + the Yellow Border Logo) and any images that are included as part of each content piece. For clarity the Logo and images may not be removed, altered, or changed in any way.

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Science News Explores

Explainer: how photosynthesis works.

Plants make sugar and oxygen with the power of water, carbon dioxide and sunlight

Green plants take in light from the sun and turn water and carbon dioxide into the oxygen we breathe and the sugars we eat.

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By Bethany Brookshire

October 28, 2020 at 6:30 am

Take a deep breath. Then thank a plant. If you eat fruit, vegetables, grains or potatoes, thank a plant too.  Plants and algae provide us with the oxygen we need to survive, as well as the carbohydrates we use for energy. They do it all through photosynthesis.

Photosynthesis is the process of creating sugar and oxygen from carbon dioxide, water and sunlight. It happens through a long series of chemical reactions. But it can be summarized like this: Carbon dioxide, water and light go in. Glucose, water and oxygen come out. (Glucose is a simple sugar.)

Photosynthesis can be split into two processes. The “photo” part refers to reactions triggered by light. “Synthesis” — the making of the sugar — is a separate process called the Calvin cycle.

Both processes happen inside a chloroplast. This is a specialized structure, or organelle, in a plant cell. The structure contains stacks of membranes called thylakoid membranes. That’s where the light reaction begins.

Let the light shine in

When light hits a plant’s leaves, it shines on chloroplasts and into their thylakoid membranes. Those membranes are filled with chlorophyll , a green pigment. This pigment absorbs light energy. Light travels as electromagnetic waves . The wavelength — distance between waves — determines energy level. Some of those wavelengths are visible to us as the colors we see . If a molecule, such as chlorophyll, has the right shape, it can absorb the energy from some wavelengths of light.

Chlorophyll can absorb light we see as blue and red. That’s why we see plants as green. Green is the wavelength plants reflect, not the color they absorb.

While light travels as a wave, it also can be a particle called a photon . Photons have no mass. They do, however, have a small amount of light energy.

When a photon of light from the sun bounces into a leaf, its energy excites a chlorophyll molecule. That photon starts a process that splits a molecule of water. The oxygen atom that splits off from the water instantly bonds with another, creating a molecule of oxygen, or O 2 . The chemical reaction also produces a molecule called ATP and another molecule called NADPH. Both of these allow a cell to store energy. The ATP and NADPH also will take part in the synthesis part of photosynthesis.

Notice that the light reaction makes no sugar. Instead, it supplies energy — stored in the ATP and NADPH — that gets plugged into the Calvin cycle. This is where sugar is made.

But the light reaction does produce something we use: oxygen. All the oxygen we breathe is the result of this step in photosynthesis, carried out by plants and algae (which are not plants ) the world over.

Give me some sugar

The next step takes the energy from the light reaction and applies it to a process called the Calvin cycle. The cycle is named for Melvin Calvin, the man who discovered it.

The Calvin cycle is sometimes also called the dark reaction because none of its steps require light. But it still happens during the day. That’s because it needs the energy produced by the light reaction that comes before it.

While the light reaction takes place in the thylakoid membranes, the ATP and NADPH it produces end up in the stroma. This is the space inside the chloroplast but outside the thylakoid membranes.

The Calvin cycle has four major steps:

• carbon fixation : Here, the plant brings in CO 2 and attaches it to another carbon molecule, using rubisco. This is an enzyme , or chemical that makes reactions move faster. This step is so important that rubisco is the most common protein in a chloroplast — and on Earth. Rubisco attaches the carbon in CO 2 to a five-carbon molecule called ribulose 1,5-bisphosphate (or RuBP). This creates a six-carbon molecule, which immediately splits into two chemicals, each with three carbons.
• reduction : The ATP and NADPH from the light reaction pop in and transform the two three-carbon molecules into two small sugar molecules. The sugar molecules are called G3P. That’s short for glyceraldehyde 3-phosphate (GLIH- sur-AAL-duh-hide 3-FOS-fayt).
• carbohydrate formation : Some of that G3P leaves the cycle to be converted into bigger sugars such as glucose (C 6 H 12 O 6 ).
• regeneration : With more ATP from the continuing light reaction, leftover G3P picks up two more carbons to become RuBP. This RuBP pairs up with rubisco again. They are now ready to start the Calvin cycle again when the next molecule of CO 2 arrives.

At the end of photosynthesis, a plant ends up with glucose (C 6 H 12 O 6 ), oxygen (O 2 ) and water (H 2 O). The glucose molecule goes on to bigger things. It can become part of a long-chain molecule, such as cellulose; that’s the chemical that makes up cell walls. Plants also can store the energy packed in a glucose molecule within larger starch molecules. They can even put the glucose into other sugars — such as fructose — to make a plant’s fruit sweet.

All of these molecules are carbohydrates — chemicals containing carbon, oxygen and hydrogen. (CarbOHydrate makes it easy to remember.) The plant uses the bonds in these chemicals to store energy. But we use the these chemicals too. Carbohydrates are an important part of the foods we eat, particularly grains, potatoes, fruits and vegetables.

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8: Photosynthesis and Respiration

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• Page ID 123932

• Teresa Friedrich Finnern
• Norco College

Plant Physiology and Regulation

Plant physiology focuses on the chemistry and physics of how plants function. Plants capture light energy and produce sugars through photosynthesis and break down these sugars through aerobic cellular respiration. They respond to a variety of environmental conditions through growth changes, life events like germination or flowering, and even, in special cases, through movement. Plants rely on soils for mineral nutrients and water, and biogeochemical cycles replenish soils with these nutrients. Once water and minerals are absorbed, they must be transported through the xylem, and this movement is driven by the loss of water vapor from leaves ( transpiration ) and the cohesive and adhesive properties of water. Likewise, sugar-rich assimilate must be moved, or translocated , through the phloem. Five main types of hormones in plants are responsible for relaying messages throughout the plant body. Throughout this unit are examples of how plants regulate their internal conditions whether it the concentration of carbon dioxide in the leaves; the positioning of stems, roots, and leaves; or the movement and retention of water (Figure \(\PageIndex{1}\)).

Attribution

Melissa Ha ( CC-BY-SA )

Photosynthesis and Respiration

Photosynthesis and aerobic cellular respiration are key metabolic pathways. Photosynthesis is essential to all life on earth; both plants and animals depend on it (Figure \(\PageIndex{2}\))​​. It is the only biological process that can capture energy that originates in outer space (sunlight) and convert it into chemical compounds (carbohydrates) that most organisms use to power their metabolism through aerobic cellular respiration or other pathways. In brief, the energy of sunlight is captured and used to energize electrons, which are then stored in the covalent bonds of sugar molecules. How long lasting and stable are those covalent bonds? The energy extracted today by the burning of coal and petroleum products represents sunlight energy captured and stored by photosynthesis almost 200 million years ago.

Curated and authored by Melissa Ha using the following sources:

• 8.1 Overview of Photosynthesis from Biology 2e by OpenStax (licensed CC-BY ). Access for free at openstax.org .
• 3 Photosynthesis from Introduction to Botany by Alexey Shipunov (public domain)
• 8.1: Energy and ATP
• 8.2: Aerobic Cellular Respiration Through aerobic cellular respiration, organisms break down sugars to produce usable energy in the form of ATP. This process consumes gaseous oxygen and releases carbon dioxide and water. There are four steps: glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation.
• 8.3: Photosynthesis Overview and Equation Photosynthesis is essential to all life on earth; both plants and animals depend on it. It is the only biological process that can capture energy that originates in outer space (sunlight) and convert it into chemical compounds (carbohydrates) that every organism uses to power its metabolism. In brief, the energy of sunlight is captured and used to energize electrons, which are then stored in the covalent bonds of sugar molecules.
• 8.4: Discovery of Photosynthesis The history of the studies done on photosynthesis dates back into the 17th century with Jan Baptist van Helmont. He rejected the ancient idea that plants take most of their biomass from the soil.
• 8.5: The Light-dependent Reactions Like all other forms of kinetic energy, light can travel, change form, and be harnessed to do work. In the case of photosynthesis, light energy is converted into chemical energy, which photoautotrophs use to build carbohydrate molecules. However, autotrophs only use a few specific components of sunlight.
• 8.6: Light-independent Reactions The enzymatic stage has many participants. These include carbon dioxide, hydrogen carrier with hydrogen (NADPH), ATP, ribulose biphosphate (RuBP), and RuBisCO along with some other enzymes. Everything occurs in the matrix (stroma) of the chloroplast.
• 8.7: Photorespiration and Photosynthetic Pathways Photorespiration occurs when RuBisCO binds to gaseous oxygen rather than carbon dioxide. It undoes the good anabolic work of photosynthesis, reducing the net productivity of the plant. Plants in different environments have adaptations to reduce photorespiration while minimizing water loss.
• 8.8: Chapter Summary

Thumbnail: Plant cells with visible chloroplasts (from a moss, Plagiomnium affine ). (CC BY SA 3.0 Unported; Kristian Peters).

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What Are the Products of Photosynthesis?

Photosynthesis is a set of chemical reactions that plants and other organisms use to make chemical energy in the form of sugar. Like any chemical reaction, photosynthesis has reactants and products . Overall, the reactants of photosynthesis are carbon dioxide and water, while the products of photosynthesis are oxygen and glucose (a sugar).

Here’s a closer look at the products of photosynthesis and the balanced equation for the reaction.

The reactants for photosynthesis are carbon dioxide and water, while the products are the sugar glucose and oxygen.

Balanced Chemical Equation for Photosynthesis

Photosynthesis actually involves many chemical reactions, but the net balanced equation is that six moles of carbon dioxide react with six moles of water to produce one mole of glucose and six moles of oxygen. Light from the Sun provides the activation energy for the reaction. Sometimes light is listed in the balanced equation as a reactant, but it’s usually omitted.

6 CO 2  + 6 H 2 O → C 6 H 12 O 6  + 6 O 2

Carbon Dioxide + Water + Light → Glucose + Oxygen

Closer Look at the Products of Photosynthesis

Photosynthesis occurs in a series of steps that are classified as light-dependent reactions and light-independent reactions. Adding up the reactants and products of these reactions gives the overall equation for photosynthesis, but it’s good to know the inputs and outputs for each stage.

Light-Dependent Reactions

The light-dependent reactions or light reactions absorb certain wavelengths of light to make adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide phosphate (NADPH). The light reactions occur in the chloroplast thylakoid membrane. The overall balanced equation for the light-dependent reactions is:

2 H 2 O + 2 NADP +  + 3 ADP + 3 P i  + light → 2 NADPH + 2 H +  + 3 ATP + O 2

Light-Independent Reactions

While the light reactions use water, the light-independent reactions use carbon dioxide. The light-independent reactions are also called the dark reactions. These reactions do not require darkness, but they don’t depend on light to proceed. In plants, algae, and cyanobacteria, the dark reactions are called the Calvin cycle. Bacteria use different reactions, including the reverse Krebs cycle.

The overall balanced equation for the light-independent reactions (Calvin cycle) in plants is:

3 CO 2  + 9 ATP + 6 NADPH + 6 H +  → C 3 H 6 O 3 -phosphate + 9 ADP + 8 P i  + 6 NADP +  + 3 H 2 O

Finally, the three-carbon product from the Calvin cycle becomes glucose during the process of carbon fixation.

Other Products of Photosynthesis

Glucose is the direct product of photosynthesis, but plants turn most of the sugar into other compounds. These are indirect products. Linking glucose units forms starch and cellulose. Cellulose is a structural material. Plants store starch or link it to fructose (another sugar) to form sucrose (table sugar).

What Is Not a Product of Photosynthesis?

On an exam, you may need to identify which chemical is not a product of photosynthesis. For the overall process, choose any answer except “glucose” or “oxygen.” It’s good to know the overall reactants and products of the light reactions and dark reactions, in case you’re asked about them. The products of the light reactions are ATP , NADPH, protons, and oxygen. The products of the dark reactions are C 3 H 6 O 3 -phosphate, ADP, inorganic phosphate, NADP + , and water.

Where Does Photosynthesis Occur?

In addition to knowing the reactants and products of photosynthesis, you may need to know where photosynthesis occurs in different organisms.

• In plants, photosynthesis occurs in organelles called chloroplasts. Photosynthetic protists also contain chloroplasts. Leaves contain the highest concentration of chloroplasts in plants. Plants obtain carbon dioxide via diffusion through leaf stomata. Water comes from the roots and travels to the leaves via the xylem . Chlorophyll in chloroplasts absorbs solar energy. Oxygen from photosynthesis exits the plant via leaf stomata.
• Photosynthesis occurs in photosynthetic bacteria in the plasma membrane. Chlorophyll or related pigments are embedded in this membrane.
• Bidlack, J.E.; Stern, K.R.; Jansky, S. (2003).  Introductory Plant Biology . New York: McGraw-Hill. ISBN 978-0-07-290941-8.
• Blankenship, R.E. (2014).  Molecular Mechanisms of Photosynthesis  (2nd ed.). John Wiley & Sons. ISBN 978-1-4051-8975-0.
• Reece J.B., et al. (2013).  Campbell Biology . Benjamin Cummings. ISBN 978-0-321-77565-8.

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show/hide words to know

ATP: adenosine triphosphate. ATP is the energy-carrying molecule of all cells...... more

Cellulose: the structural material found in the cell wall in most plants. Cellulose is used to make many products, including paper and cloth...  more

Electron transport chain: cell process that uses electrons to generate chemical energy...  more

Ion: an atom or molecule that does not have the same number of electrons as it has protons. This gives the atom or molecule a negative or positive charge...  more

Light-dependent reaction: the first part of photosynthesis where (sun)light energy is captured and stored by a plant...  more

Molecule: a chemical structure that has two or more atoms held together by a chemical bond. Water is a molecule of two hydrogen atoms and one oxygen atom (H2O)...  more

Protein: a type of molecule found in the cells of living things, made up of special building blocks called amino acids.

Starch: made by all green plants and used to store energy for later use...  more

Thylakoid: the disk-shaped parts of a plant cell where light-dependent reactions occur...  more

In with One Energy and out with Another

The light-dependent reactions take place in the thylakoid membrane, inside chloroplasts. Since they are light 'dependent' reactions, you can guess that these reactions need light to work. Remember that the purpose of this first part of photosynthesis is to convert sunlight energy into other forms of energy?

The light-dependent reactions of photosynthesis require sunlight. Image by Mell27.

Plants cannot use light energy directly to make sugars. Instead, the plant changes the light energy into a form it can use: chemical energy. Chemical energy is all around us. For example, cars need the chemical energy from gasoline to run. The chemical energy that plants use are stored in ATP and NADPH. ATP and NADPH are two kinds of energy-carrying molecules. These two molecules are not only in plants, as animals use them as well.

A Recipe for Energy

Plants need water to make NADPH. This water is broken apart to release electrons (negatively charged subatomic particles). When water is broken it also creates oxygen, a gas that we all breathe.

The electrons must travel through special proteins stuck in the thylakoid membrane. They go through the first special protein (the photosystem II protein) and down the electron transport chain. Then they pass through a second special protein (photosystem I protein).

Photosystem I and Photosystem II

Wait a second... first electrons go through the second photosystem and second they go through the first? That seems really confusing. Why would they name the photosystems that way?

Water molecules are broken down to release electrons. These electrons then move down a gradient, storing energy in ATP in the process. Image by Jina Lee.

Photosystem I and II don't align with the route electrons take through the transport chain because they weren't discovered in that order. Photosystem I was discovered first. Later, photosystem II was discovered and found to be earlier in the electron transport chain. But it was too late, the name stuck. Electrons first travel through photosystem II and then photosystem I.

The Electron Transport Chain

While at photosystem II and I, the electrons gather energy from sunlight. How do they do that? Chlorophyll, which is present in the photosystems, soaks up light energy. The energized electrons are then used to make NADPH. The electron transport chain is a series of molecules that accept or donate electrons easily. By moving step-by-step through these, electrons are moved in a specific direction across a membrane. The movement of hydrogen ions are coupled with this. This means that when electrons are moved, hydrogen ions move too. ATP is created when hydrogen ions are pumped into the inner space (lumen) of the thylakoid. Hydrogen ions have a positive charge. Like in magnets, the same charges repel, so the hydrogen ions want to get away from each other. They escape the thylakoid through a membrane protein called ATP synthase. By moving through the protein they give it power, like water moving through a dam. When hydrogen ions move through the protein and down the electron transport chain, ATP is created. This is how plants turn to sunlight into chemical energy that they can use.

The Calvin Cycle: Building Life from Thin Air

How does something like air become the wood of a tree? The answer lies in what makes up the air.

How can the air surrounding a tree be turned into tree material? Through a complex set of reactions that use the carbon from the air to make other materials. Image by André Karwath.

The air holds different elements like oxygen, carbon, and nitrogen. These elements make up molecules like carbon dioxide (CO2). Carbon dioxide is made out of one carbon atom and two oxygen atoms. Plants take the carbon atom from carbon dioxide and use it to build sugars. This is done using the Calvin cycle. The Calvin cycle occurs inside chloroplasts, but outside the thylakoids (where ATP was created). The ATP and NADPH from the light-dependent reactions are used in the Calvin cycle. Parts of the Calvin cycle are sometimes called light-independent reactions. But don't let the name fool you... those reactions do require sunlight to work. The protein RuBisCO also helps in the process to change carbon from the air into sugars. RuBisCO works slowly, so plants need a lot of it. In fact, RuBisCO is the most abundant protein in the world! The products of the Calvin cycle are used to make the simple sugar glucose. Glucose is used to build more complex sugars like starch and cellulose. Starch stores energy for the plant and cellulose is the stuff of which plants are made.

Images via Wikimedia Commons. Seedling image by Bff.

Read more about: Snacking on Sunlight

View citation, bibliographic details:.

• Article: Photosynthesis
• Author(s): Heather Kropp, Angela Halasey
• Publisher: Arizona State University School of Life Sciences Ask A Biologist
• Site name: ASU - Ask A Biologist
• Date published: May 25, 2017
• Date accessed: May 2, 2024
• Link: https://askabiologist.asu.edu/photosynthesis

Heather Kropp, Angela Halasey. (2017, May 25). Photosynthesis. ASU - Ask A Biologist. Retrieved May 2, 2024 from https://askabiologist.asu.edu/photosynthesis

Chicago Manual of Style

Heather Kropp, Angela Halasey. "Photosynthesis". ASU - Ask A Biologist. 25 May, 2017. https://askabiologist.asu.edu/photosynthesis

MLA 2017 Style

Heather Kropp, Angela Halasey. "Photosynthesis". ASU - Ask A Biologist. 25 May 2017. ASU - Ask A Biologist, Web. 2 May 2024. https://askabiologist.asu.edu/photosynthesis

Plants need chemical energy to grow and survive. But how do they convert energy in sunlight into chemical energy?

Snacking on Sunlight

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Cooperation of an external carbonic anhydrase and HCO 3 – transporter supports underwater photosynthesis in submerged leaves of the amphibious plant Hygrophila difformis

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Genki Horiguchi, Ryoma Oyama, Tatsuki Akabane, Nobuhiro Suzuki, Etsuko Katoh, Yusuke Mizokami, Ko Noguchi, Naoki Hirotsu, Cooperation of an external carbonic anhydrase and HCO 3 – transporter supports underwater photosynthesis in submerged leaves of the amphibious plant Hygrophila difformis , Annals of Botany , Volume 133, Issue 2, 1 February 2024, Pages 287–304, https://doi.org/10.1093/aob/mcad161

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HCO 3 – can be a major carbon resource for photosynthesis in underwater environments. Here we investigate the underlying mechanism of uptake and membrane transport of HCO 3 – in submerged leaves of Hygrophila difformis , a heterophyllous amphibious plant. To characterize these mechanisms, we evaluated the sensitivity of underwater photosynthesis to an external carbonic anhydrase (CA) inhibitor and an anion exchanger protein inhibitor, and we attempted to identify components of the mechanism of HCO 3 – utilization.

We evaluated the effects of the external CA inhibitor and anion exchanger protein inhibitor on the NaHCO 3 response of photosynthetic O 2 evolution in submerged leaves of H. difformis . Furthermore, we performed a comparative transcriptomic analysis between terrestrial and submerged leaves.

Photosynthesis in the submerged leaves was decreased by both the external CA inhibitor and anion exchanger protein inhibitor, but no additive effect was observed. Among upregulated genes in submerged leaves, two α-CAs, Hd α -CA1 and Hd α -CA2 , and one β-carbonic anhydrase, Hd β -CA1 , were detected. Based on their putative amino acid sequences, the α-CAs are predicted to be localized in the apoplastic region. Recombinant Hdα-CA1 and Hdβ-CA1 showed dominant CO 2 hydration activity over HCO 3 – dehydration activity.

We propose that the use of HCO 3 – for photosynthesis in submerged leaves of H. difformis is driven by the cooperation between an external CA, Hdα-CA1, and an unidentified HCO 3 – transporter.

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AP®︎/College Biology

Course: ap®︎/college biology   >   unit 3.

• Photosynthesis
• Intro to photosynthesis
• Breaking down photosynthesis stages
• Conceptual overview of light dependent reactions
• The light-dependent reactions

The Calvin cycle

• Photosynthesis evolution
• Photosynthesis review

Introduction

Overview of the calvin cycle, reactions of the calvin cycle.

• Regeneration. One G3P molecule leaves the cycle and will go towards making glucose, while five G3Ps must be recycled to regenerate the RuBP acceptor. Regeneration involves a complex series of reactions and requires ATP.
• Carbon fixation. A CO 2 ‍   molecule combines with a five-carbon acceptor molecule, ribulose-1,5-bisphosphate ( RuBP ). This step makes a six-carbon compound that splits into two molecules of a three-carbon compound, 3-phosphoglyceric acid (3-PGA). This reaction is catalyzed by the enzyme RuBP carboxylase/oxygenase, or rubisco . Details of this step The first stage of the Calvin cycle incorporates carbon from CO 2 ‍   into an organic molecule, a process called carbon fixation . In plants, atmospheric CO 2 ‍   enters the mesophyll layer of leaves by passing through pores on the leaf surface called stomata. It can then diffuse into mesophyll cells, and into the stroma of chloroplasts, where the Calvin cycle takes place. Simplified diagram (showing carbon atoms but not full molecular structures) illustrating the reaction catalyzed by rubisco. Rubisco attaches a carbon dioxide molecule to an RuBP molecule, and the six-carbon intermediate thus produced breaks down into two 3-phosphoglycerate (3-PGA) molecules. In the first step of the cycle, an enzyme nicknamed rubisco (RuBP carboxylase-oxygenase) catalyzes attachment of CO 2 ‍   to a five-carbon sugar called ribulose bisphosphate (RuBP ). The resulting 6-carbon molecule is unstable, however, and quickly splits into two molecules of a three-carbon compound called 3-phosphoglycerate (3-PGA). Thus, for each CO 2 ‍   that enters the cycle, two 3-PGA molecules are produced. The actual molecular structures are show below: Diagram showing the molecular structures of RuBP and carbon dioxide, the unstable six-carbon intermediate formed when they combine, and the two 3-PGA molecules produced by the intermediate's breakdown.
• First, each molecule of 3-PGA receives a phosphate group from ATP, turning into a doubly phosphorylated molecule called 1,3-bisphosphoglycerate (and leaving behind ADP as a by-product).
• Second, the 1,3-bisphosphoglycerate molecules are reduced (gain electrons). Each molecule receives two electrons from NADPH and loses one of its phosphate groups, turning into a three-carbon sugar called glyceraldehyde 3-phosphate (G3P) . This step produces NADP + ‍   and phosphate ( P i ‍   ) as by-products.
• Regeneration. Some G3P molecules go to make glucose, while others must be recycled to regenerate the RuBP acceptor. Regeneration requires ATP and involves a complex network of reactions, which my college bio professor liked to call the "carbohydrate scramble." 1 ‍  

Summary of Calvin cycle reactants and products

• 1 ‍   G3P molecule exits the cycle and goes towards making glucose.
• 5 ‍   G3P molecules are recycled, regenerating 3 ‍   RuBP acceptor molecules.
• ATP. 9 ‍   ATP are converted to 9 ‍   ADP ( 6 ‍   during the reduction step, 3 ‍   during the regeneration step).
• NADPH . 6 ‍   NADPH are converted to 6 ‍   NADP + ‍   (during the reduction step).

Attribution:

• " The Calvin cycle ," by OpenStax College, Concepts of Biology, CC BY 4.0 . Download the original article for free at http://cnx.org/contents/[email protected] .
• " Using light energy to make organic molecules ," by OpenStax College, Biology, CC BY 4.0 . Download the original article for free at http://cnx.org/contents/[email protected] .

Works cited:

• Koning, R. E. (1994). Calvin cycle. In Plant physiology information website . Retrieved from http://plantphys.info/plant_physiology/calvincycle.shtml .

References:

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The final products of photosynthesis in plants are

The correct option is c glucose and oxygen green plants use sunlight to make their food and the process is called photosynthesis. it requires sunlight, chlorophyll, water, and carbon dioxide gas. the chlorophyll present in leaves absorbs light energy from the sun and converts it into chemical energy. glucose is the simple food which is prepared first in the process of photosynthesis. glucose and oxygen (formed during splitting of water) are the final products of photosynthesis. the glucose is stored in the form of starch in the plant cells..

How plants do photosynthesis and respiration at the same time in the day as in respiration,oxygen is inhaled and carbon dioxide is exhaled and in photosynthesis,carbon dioxide is inhaled and oxygen is exhaled.So they are opposite.So how do they carry out both the processess at the same time?